A dual fuel engine can typically operate in two modes. In a strictly liquid fuel mode a liquid fuel, such as diesel fuel, is injected directly into an engine cylinder or a precombustion chamber as the sole source of energy during combustion. In a dual fuel mode a gaseous fuel, such as natural gas, is mixed with air in an intake port of a cylinder and a small amount or pilot amount of diesel fuel is injected into the cylinder or the precombustion chamber in order to ignite the mixture of air and gaseous fuel. In the past, the transition from a liquid fuel operating mode to a dual fuel operating mode, or from a dual fuel operating mode to a liquid fuel operating mode, could result in a series of undesired engine speed fluctuations such as engine speed surges and droops during such transitions.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.